Closure operator

ABSTRACT

A closure operator to effect remote, failsafe opening and closing of a damper, particularly a multi-fold or interlocking slat curtain damper. A frame or shell envelops a damper curtain which is capable of opening and closing an air passage through the frame or shell. A housing containing an electromechanical curtain operator is optionally positioned within or outside the frame or shell. The curtain is lifted by a tray connected to two wire cables, in response to the winding of the cable upon a takeup drum located within the housing. The principal components of the electromechanical curtain operator are a motor, planetary gear train and its associated latch mechanism which form a clutch, cable drum, speed control brake, and limit switch assembly. All of the foregoing components are protectively contained within an operator housing which is formed with an irregular shaped projecting finger which engages a mating opening formed in a damper supported bracket or in a baffle which isolates the curtain in its open position.

ilited States Patent 1191 Roberts 11] 3,752,208 1451 Aug. 14, 1973 CLOSURE OPERATOR Frank D. Roberts, North Reading, Mass.

[73] Assignee: Rixson-Firemark Inc., Franklin Park, Ill.

[22] Filed: Apr. 12, 1971 [21] App]. No.: 132,959

[75] Inventor:

' [52] us. or. 160/1, 160/84, 74/785 [51] Int. Cl. E05! 15/20 [58] Field of Search 160/1, 5, 6, 84; 74/785; 98/110, 121

[56] References Cited UNITED STATES PATENTS 6/1965 Maurer et al. 6/1961 Smith....

Primary ExaminerPeter M. Caun AttorneyAugustus G. Douvas [57] ABSTRACT A closure operator to effect remote, failsafe opening and closing of a damper, particularly a multi-fold or interlocking slat curtain damper. A frame or shell envelops a damper curtain which is capable of opening and closing an air passage through the frame or shell. A housing containing an electromechanical curtain operator is optionally positioned within or outside the frame or shell. The curtain is lifted by a tray connected to two wire cables, in response to the winding of the cable upon a takeup drum located within the housing. The principal components of the electromechanical curtain operator are a motor, planetary gear train and its associated latch mechanism which form a clutch, cable drum, speed control brake, and limit switch assembly. All of the foregoing components are protectively contained within an operator housing which is formed with an irregular shaped projecting finger which engages a mating opening formed in a damper supported bracket or in a baffle which isolates the curtain in its open position.

7 Claims, 13 Drawing Figures Patented Aug. 14, 1973 3,752,208

5 Sheets-Sheet l INVENTOR Frank D. Roberts Attornev Patented Aug. 14, 1973 3,752,208

5 Sheets$heet :3

INVENTOR Frank D. Roberts Attornev Patented Aug. 14, 1973 5 Sheets-Sheet 3 INVENTOR Frank D. Roberts By A'riornev Patented Aug. 14, 1973 5 Sheets-Sheet 4 R O T N E V N FIG. IO.

Frank D. Roberts I Patented Aug. 14, 1973 5 Sheets-Sheet I N V E N TOR Frank D. Roberts s /flfm FIG. l2.

Attorney CLOSURE OPERATOR BACKGROUND OF THE INVENTION In recent years an increased emphasis has been placed upon the need for improved safety devices to minimize the loss of life and property occurring from the products of combustion. The prevalence of large buildings with air conditioning and ventilating ducts through walls requires the installation of dampers in these openings to isolate an unsafe building area from the remaining areas in the event of a hazardous condition. These dampers must close reliably in the event of a fire, otherwise the products of combustion will travel through the damper containing ducts or fire walls. Additionally, the dampers should preferably be capable of restoration to an open condition without extensive manual servicing occasioned by the necessary replacement of components, such as fusible links, or the rearming of the damper operator by reengaging various linkages.

The damper control system should also be failsafe in the sense that a power failure, or other circuit malfunction in the undesired'condition detecting system will automatically close the damper. Additionally, upon restoration of power, or correction of the circuit malfunction, the damper must be operated without the necessity for a serviceman to obtain access to the damper to replace or team components.

DESCRIPTION OF THE PRIOR ART Almost invariably damper control devices of the prior art have employed fusible links. The melting of these links effects damper closure by activating a closer mechanism. The use of fusible links is generally unsatisfactory due to the delay involved in melting the link which enables the products of combustion to spread. Additionally, such systems are not failsafe; and they require manual replacement of each link before the dampers are readied for further operation.

Examples of fusible link systems are shown in U.S. Pat. Nos. 3,467,163, 3,337,991 and 3,273,632.

Other remotely related patents have described louver, vane or door positioners. The controls for these devices have in some instances dispensed with fusible links, but in most instances, the systems are either not failsafe, or alternatively, upon occurrence of an undesired condition, manual restoration of the system is required.

Examples of these systems appear in U.S. Pat. Nos. 3,249,148, 3,219,104, 3,207,273, 3,177,367,

3,164,404 and 2,980,970. The applicants pending ap plication for Closure Operator, Ser. No. 882,827 filed Dec. 8, 1969, discloses a damper operator to which this invention presents several improvements outlined in the following summary.

SUMMARY OF THE INVENTION The closure operator of this invention provides electromechanical structure, the principal components of which are all contained within a housing mounted on failsafe closing of the damper upon smoke detection or system failure, and (3) to reopen automatically the damper when the problem which caused closing is corrected.

The principal components of the operator, all contained within the damper mounted housing, are the drive motor, planetary gear train and its associated latch mechanism which form a clutch, cable drum, speed limiting brake, and a limit switch assembly.

The motor is preferably a shaded pole, gear head motor which includes an integral rotor brake to eliminate motor rotation during a power-off condition, thus holding the damper open.

The shaft output of the motor is coupled to the sun gear of a planetary gear train. The sun gear rotates four planet gears rotatably mounted on shafts which are fixed to a planet carrier. The drive motor does not rotatably drive the drum, however, unless an internal gear ring which engages the planet gears is latched.

The latch mechanism includes an electromagnetically operated lever which carries a latch bar to engage a spring loaded pawl exteriorly mounted on the internal gear ring. When the pawl is latched, the internal gear ring is latched thereby coupling motor shaft output to the drum. The motor driven drum takes up the cable to elevate the curtain lift tray. This operation opens the damper curtain.

The limit switch assembly includes a threaded actuator sleeve which rotates ineffectively on a shaft extension affixed to the drum until the sleeve engages a shaft stop. When stop engagement occurs, the sleeve rotates with the shaft extension. As the sleeve rotates fixedly driven by the shaft, an actuating finger thereon opens a microswitch to deenergize the motor. This action limits the open folding of the curtain.

The internal gear ring of the planetary gear remains engaged by the latch. Accordingly, the motor brake prevents unwinding of the drum which would close the curtain.

When a curtain closing condition occurs, the internal gear ring is unlatched. This enables the drum to unwind quickly relieved of the inertia of much of the planetary gear and all of the motor parts.

A multiple disc centrifugal brake is directly coupled to a portion of the shaft extension which carries the limit switch sleeve. The brake is effective to limit the closing speed of the damper to a safe, non-destructive range.

Important structural features of the invention are as follows:

I. The application of a planetary gear train as a latch and release component allows all gears to remain in constant mesh and still provide for complete mechanical disconnect between the drum and motor during a curtain release cycle. This complete disconnect is iming the inertia of the components and thus the overstressing and resulting fatigue.

4. The speed control brake reduces the inertia of rotating parts within the control and thus eliminates the overrunning tendency of the drum which would severly stress the cable.

5. The limit switch and the motor control switch are totally enclosed within the unit and thus simplify installation and reduce external wiring.

6. The design of the limit switch actuator causes it to relate only to shaft rotation irrespective of axial shaft movement and thus dependently determines the full open stop position of the operator while providing a simple method of field adjustment of this stop position.

7. The curtain cable is attached to the cable drum with an anchor and nut which allows simple attachment or removal of cable from the drum for simplified maintenance or installation.

8. The case and mounting brackets are so designed as to allow simple one-handed removal or installation of the control for maintenance through a hand hole in an existing ventilation system.

9. The operator housing may be mounted within an air duct or outside the duct if required by a particular application.

10. All of the principal operating mechanism is totally enclosed within a dustproof steel housing.

11. All electrical connections may be made in space provided within the operator housing itself or prewired for external connection where desirable.

DETAILED DESCRIPTION OF THE DRAWINGS In order that all of the structural features for attaining the objects of this invention may be. understood, reference is herein made to the following drawings wherein:

FIG. 1 is a fragmentary perspective view showing the closure operator of this invention typically positioned within the upper portion of the damper frame and applied to a multi-fold curtain damper with the individual folds shown in the damper closed position;

FIG. 2 is a fragmentary perspective view showing the lower portion of the damper of FIG. 1 with the curtain lift tray resting on the bottom of the frame;

FIG. 3 is a fragmentary view of the upper portion of the damper showing theclosure operator removed from the damper frame;

FIG. 4 is a fragmentary view of the exterior of the damper frame showing the alternate application of the closure operator to the exterior of the frame;

FIG. 5 is a schematic circuit diagram showing the electrical connection of the principal components of the closure operator to a condition detector (smoke or heat, for example) to effect failsafe operation of the damper;

FIG. 6 is a longitudinal section view of the closure operator housing taken along line 6--6 of FIG. 8 and showing the internal components of the operator mechanism;

FIG. 7 is an end-view taken along line 77 of FIG. 6, showing the limit microswitch with its actuating contact assembly;

FIG. 8 is a perspective view of the closure operator with the housing cover removed to show the internal components of the operator mechanism;

FIG. 9 is a section view taken along line 9-9 of FIG. 6 showing the planetary gear train and its electromagnetically operated latch mechanism;

FIG. 10 is an exploded view showing the principal components of the planetary gear train, a portion of the latch, and the motor gear and brake housing which carries he foregoing components;

FIG. 11 is an exploded view showing the principal components of the speed control brake and the limit switch contact assembly;

FIG. 12 is a fragmentary perspective view showing the cable drum; and

FIG. 13 is a fragmentary view of the damper frame showing an alternative mounting bracket to provide a slot for the box housing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2, the opening and closing of multi-fold curtain damper l is controlled by a closure operator, the main components of which include curtain operator 2, wire cable sections 3, 4 which are a continuous length, curtain lift tray 5 to which the ends of cables 3, 4 are coupled, single cable pulleys 6 and 7, and double cable pulley 8 which includes two single pulleys 8a and 8b. Cable clamp 9 fixes adjustably cable 3 to tray 5.

Multi-fold curtain damper 1 is of conventional construction in which curtain 10 is formed from a plurality of sheet metal folds. Alternatively, the curtain may be formed from hinged slats. Curtain 10 is enveloped or housed within frame or shell 11 which includes side wall 12, top 13, side wall 14 and bottom 15.

Curtain 10 is sandwiched between guide angles 16 and 17, both of which angles are formed into continuous individual rectangles. The guide angles constrain possible lateral movements of curtain 10 within permissible limits.

A pair of baffle plates 18 extend between the upper portion of guide angles 16 and 17 so that curtain 10 is located entirely between these plates when folded. Thus, dirt and other foreign particles are not collected excessively within the deep recesses of curtain 10 when this curtain is in the elevated position.

The electromechanical components comprising curtain operator 2 are housed within box housing 19 which includes a removable cover having two separated cover sections 20 and 21. Cables 3, 4 extend through opening 22, defined by the separation of sections 20 and 21 to pass through the cable anchor 23 (FIG. 12) of takeup drum 24.

As is hereafter explained in detail, when drum 24 and its anchor 23 rotate in a counterclockwise direction (as is viewed in FIG. 12) cables 3, 4 are wound around the drum 24, thus elevating tray 5 and lifting curtain 10 to a folded position between baffle plates 18.

FIG. 3 shows the manner in which curtain operator 2 is preferably applied to curtain damper 1. Box housing 19 is formed with projecting angle finger 25, and baffle 18 is notched to form an angle opening 26 which receives finger 25. In particular, when housing 19 is moved upwardly in the direction of broken lines 27, 28 to assume its operating position as indicated by broken line 29, bracket 34 is engaged by housing opening 22 by rotating the housing slightly and finger 25 is inserted within opening 26. Bracket 30 is then bolted to side wall 12 to fix housing 19 in the position shown in FIG.

FIG. 4 shows an alternate application of curtain operator 2 to the exterior of damper frame 1 1. In certain installations in which the damper may be mounted within relatively inaccessible ductwork, the installation of FIG. 4 provides easier access tocurtain operator v2. In this alternate application, damper side wall 12 is formed with an opening 31 through which cables.3, 4 pass to make connection to the cable anchor123 (FIG. 12). Gasket 32 is tightly sandwiched between housing 19 and side wall 12 when the box is screwed to side wall 12 to assume the position shown in broken line 33.

The schematic circuit diagram of FIG. 5 shows .the electrical connection of the principalcomponents of the curtain operator to condition detector input terminals (smoke or heat, for example) to effect failsafe operation of the damper.

Additionally, the principal mechanical andrelectrical components contained within housing 19 are also shown diagrammatically. These components are .the motor 40, planetary gear train 41, latch mechanism42, cable drum 24, speedeontrol brake43, and limit switch assembly 44.

Motor 40 .is a shaded pole, gear head motor with motor brake toeliminate motor rotation during power off condition (in thiscondition damper l is held .open).

Planetary gear train 4.1 includes sun gear 410 which is mechanically coupled to the shaft output of motor 40. Four planet gears 41b are carried .by planet carrier 41c. The gears 41a, b are :housed within internal gear ring 41d. Gear ring41d carries a pair of springactuated pawls4le. Planetary gear train 41 serves two functions: (I) when latch bar 42a of latch mechanism 42 is elevated into engagement with a pawl 4le, internal gear ring 41d is restrained thereby enabling the :rotating sun gear 410 driven by motor 40 -.to also rotate planet carrier 41c and rotate drum 24; and (2) when .latch .bar 42a .is disengaged from pawl 4.1e, drum 24 .is .disconnected from motor 40 as gear .ring 41d freely .rotates.

Latch mechanism 42 includes a lever 42bpivoted at one end andactuated at the otherend by anarmature 420 which is responsive to the energization 'of electromagnet 42d. The energization of electromagnet 42d lifts armature 42c, thereby causing latch bar 42a to .engage pawl 4le and contact actuator segment 42c to close normally open contact 42f. Latch mechanism '42 serves two functions; (1,) the principal function is tosecure the gear ring 41d and also to release this:ring;.and (2) to operate motor control switch 42f.

Cable drum 24 is rotated by planet carrier 410 to wind cables 3, 4 around the drum thus lifting tray.5 and folding curtain 10.

Speed control brake 43 is a multiple disc centrifugal brake which includes a hub 43a carryinga stop ring-43b (see FIGS. 6 and 11). The hub also carries three rotating brake discs 43c and two weights 43d. When the .hub rotates rapidly in response to the freeing of pawl 41c from latch bar 42a, weights 43d are thrown outwardly relative their pivots to force the three rotating brake discs 43:: into friction contact with static plates 43. The purpose of brake 43 is to limit the closing speed of the damper to a value which will-prevent destruction of the curtain and the damper.

Limit switch assembly 44 includes a normally closed micoswitch 44a which is actuated to an open position by an actuating contact assembly which includes an actuating finger 44b (see FIG. 7). The purpose of the limit switch assembly is to control the maximum open position of the damper curtain 10.

The schematic circuitry incorporates a condition responsive detector and amplifier unit 45 which is failsafe in operation. In particular, if all of the components of .detector and amplifier circuitry 45 are properly operative, damper lwill open upon the manual closure of master operate switch46. If, however, detector and .amplifierunit 45 is'not properly operative, or, alterna- -46.'That .is, closure of switch 46 applies line voltage from .lin'eterminals 49-and 50 to amplifier A ofdetector .andamplifier-unit 45. The application of line voltage to :amplifier A energizes amplifier output -relay 51,

.thereby'closing normally open contact 51a.

The closure of contact 51a applies line voltage to the winding of power relay 52. With this occurrence, nor- .mally open power relay contact 52a is closed, thereby applying .linevoltageto full-wave rectifier bridge terminals '53, 54. The :direct voltage output of the bridge appearingat output terminals and 56, energizes electromagnet 42d.

The energization of electromagnet 42d draws arma' ;ture--42czupwardly thereby closing'motor contact-42f.

"When motor contact 42f is closed, motor 40 is energized by line voltage applied through closed microswitch contact 44a.

When motor 40 is energized, shaft-outputrotates sun I gear 41a. In view of the fact thatlatch bar 42ais-lifted :into engagement with pawl 41e carried on gear ring 41d, :planet carrier 41c is also rotated by the-rotating planet gears 41b.

Ihe'rotation-of planet .carrier 41c rotates drum 24, thus :winding cables 3,4 around the drum to elevate curtain 10 to the open or folded position.

When curtain 10 is elevated to its desired open positionbehind baffles 18, actuating finger'44b, opens limit switch contact 440. When contact 44a is opened, the energizing circuit for motor 40 previously established is opened. Accordingly, rotating shaftoutput at motor 40 is ceased. It should be noted, however, that the .openingaofmicroswitch contact 44a does not open the energizing .circuit for electromagnet 42d. Accordingly, the planetary gear is locked, thus drum 24 is still me- :chanicallycoupled to motor40. Since motor 40 has an internal brake which is applied when the motor is deenergized,-drum .24'does not rewind to lower the curtain.

Assuming curtain 10 to be in the lifted position, in the event-of l a power failure appearing at terminals "49 and 50, (.2) an opening of manual operate switch 46, 3) a malfunctioning of detector and amplifier unit 45,

or (4) "the sensing of an undesired condition .at input terminals '47, 48, then amplifier output relay 5.1 releases its contact 51a. This in turn causes deenergization of power-relay 52 which in turn releases its contact 520.

With this occurrence, line voltage is no longer applied to the rectifying bridge to energize electromagnet 42d. The electromagnet, therefore, releases armature 42c which enables lever 42b to pivot downwardly carrying'with it latch bar 42a and switch actuator segment Planet carrier 41c is thus released from the motor 40 brake. Drum 24 starts a rapid unwind rotation in response to the forces exerted by folded curtain 10. Weights 43d of speed control brake 43, rotate responsively throwing the weights outwardly as the centrifugal forces increase in intensity. Before the curtain drops at an excessive speed, the weights 43d force the three rotating brake discs 43c against the static plates 43c, thereby restraining the curtain drop.

It should be noted that after curtain 10 begins to drop in response to the unwinding of drum 24, microswitch 44a again closes due to the fact that actuating finger 44b is removed from the microswitch. The closing of microswitch 44a does not, however, complete the motor 40 energizing circuit, because motor contact 42f is opened by the prior release of armature 420.

After the particular condition which caused curtain 10 to drop has been corrected, curtain 10 is elevated by the circuit and mechanical component operation previously described.

FIGS. 6 and 8 show the cooperative relationship of the principal mechanical and electrical components which comprise curtain operator 2. The interior cavity of housing 19 is subdivided into three major compartments by separation plates 60 and 61. Motor 40, planetary gear train 41, and latch mechanism 42 are located in the right compartment; drum 24 and its drive shaft 62 extend through the central compartment formed between plates 60 and 61; and speed control brake 43 and limit switch assembly 44 are located in the left compartment.

Motor 40 includes a brake at one end (not shown) and a reduction gear housing 40a at the opposite end, with rotating shaft output appearing at shaft 40b. Housing 40a is formed with a projecting post 40c. Post 40c receives and fixedly holds pivot pin 42g. As will be hereafter explained with reference to FIG. 9, latch bar 42a carried on lever 42b, both a part of latch mechanism 42, pivots through a limited angular range on pivot pin 42g.

Tubular sun gear coupler 41f is fixed to shaft 40b by means of pin 41 whose ends are housed within collar 41h. Sun gear 41a is fixed to the left end of coupler 41f to rotate responsively with shaft 40b. Annular nylon bearing 41: is inserted between gear ring 41d and collar 41h. In particular, gear ring 41d is held stationary when a pawl 41e is engaged by latch mechanism 42 as hereafter explained.

When all pawls 41e are disengaged, sun gear 41a rotates the four. planet gears 41b about stationary planet carrier 41c. The internal gear teeth of gear ring 41d (FIG. 9) engage the rotating planet gears 41d thereby causing the gear ring to rotate responsively with the planet gears.

When a pawl 4le is latched, planet gears 41b rotate within the gear ring 41d causing planet carrier 410 to rotate responsively with motor shaft 40b. Planet carrier 410 is fixed to drum drive shaft 62 by split tubular pin 63 (see FIG. 10). Likewise drum 24 is fixed to drive shaft 62 by anchor 23 (see FIG. 12). Accordingly, drum 24 rotates responsively with planet carrier 41c. Drive shaft 62 is supported by plastic bearings 64 and 65 carried by separation plates 60 and 61, respectively. Plastic bearing 76 centers and supports the planetary gear train on shaft 62.

Square hub 43a of speed control brake 43 is carried by the left end of drive shaft 62 (see FIG. 11). The hubrotates responsively with drive shaft 62. Rotating brake discs 430 are each formed with a square central hole (see FIG. 11) through which hub 43a passes with a relatively loose fit. These discs, therefore, rotate responsively with the hub. A pair of static brake plates 43:: are carried by the four support posts 66 which are fixed to separation plate 61. Centrifugal weights 43d are pivotally attached to hub 43a by a pair of weight pivot pins 43]. The weights 43d apply a braking force against rotating brake discs 43c which force these discs into friction braking engagement with plates 43c during the rapid unwind operation of drum 24 during the lowering of curtain 10. v

Bracket 70 (FIG. 6) carries microswitch 44a of limit switch assembly 44. Contact actuating plunger 44c (FIG. 7) projects from the switch body so as to be operated by actuating finger 44b carried by finger support 44d. Finger support 44d is clamped fixedly to threaded sleeve 44e (FIG. 1 1) by means of nut and bolt 44f. The internal threads of sleeve 44e engage the external threads of drive shaft extension 71 (FIG. 11). During the cable winding rotation of drum 24, actuating finger 44b rests gently against switch plunger 440. However, insufficient force is exerted against the plunger to open the microswitch contact (see circuit of FIG. 5) until sleeve 44a is received sufficiently by threaded shaft extension 71 so that sleeve 44e abuts against stop shoulder 72.

When sleeve 44e contacts stop 72, actuating finger 44b is rotated with sufficient force to depress switch plunger 440. This operation opens microswitch contact 44a, thus deenergizing drive motor 40. Further elevation of curtain 10 is thus limited by limit switch assembly 44.

When a condition occurs, such as smoke or fire, electromagnet 42d is deenergized (FIG. 5) thereby releasing planet carrier 41c. The release of planet carrier 41c enables drum 24 to unwind cables 3, 4 lowering curtain 10. At the same time, finger support 44d rotates counterclockwise (see FIG. 7) until stop finger 44g contacts the bottom of microswitch body 44a. This stop finger contact enables threaded sleeve 44e to unwind relative threaded shaft extension 71.

From the foregoing operation of limit switch assembly 44, it is seen that the relative rotation of sleeve 44:: on shaft extension 71 determines when limit switch 44a will be opened to prevent further raising of curtain 10. Washers or other space inserts may be placed over shaft extension 71, to adjust the limit elevation of ourtain 10 as desired. Preferably, however, the limit switch should be adjusted by loosening bolt 44f, thus releasing bracket 44d from threaded sleeve 44e.-Sleeve 44c is then rotated on thread 71 to a proper location and bolt 44f retightens to complete the adjustment.

FIG. 9 shows the details of the latch mechanism 42 in association with planetary gear train 41. Electromagnet 42d is mounted relative housing 19 by bracket 73. When this electromagnet is energized, armature 42c is drawn to the left (upwardly in FIG. 8), pivoting lever 42b about pivot pin 42g. The pivoting of lever 42b causes actuator segment 42e to close motor contact switch 42f (FIG. 5) thereby energizing motor 40. Additionally, notched latch bar 42a catches the projecting end of a pawl 41e which rotates responsively with internal gear ring 41d in a clockwise direction. The engagement of pawl 41e stops the clockwise rotation of gear ring 41d, enabling sun gear 41a to rotate planet gears 41b. The rotation of planet gears 41b causes these gears to travel in a counterclockwise direction about the internal gear teeth of the locked gear ring 41d. This planet gear rotation causes the planet carrier 41c to drive drum 24 in a direction to wind cables 3, 4 about drum 24 thus elevating curtain l0.

Armature spring 42h permits limited relative movement between armature 42c and lever 42b; and lever spring 42f assists magnet 42d in overcoming the forces of gravity on latch lever 42b and armature 420.

As is shown in FIG. 10, pawls 41e are pivotally mounted relative internal gear 41d by a pawl pivot pin 41j. The leading edge of each pawl 4le (see FIGS. 8, 9) is projected outwardly by a wire spring 41]: so that latch bar 42a may be engaged. The use of a pivoted and spring-loaded latch pawl 4le eliminates the possibilities of the control being hung up if the electromagnet 42d should be energized when the pawl is in line with the raised portion 42 (FIG. 9) of the latch lever 42b preventing motor control switch 42f from being closed.

FIG. 1 1 shows the speed control brake 43. The structure and operation of most of the elements of the brake have previously been explained with the exception of the yokes 43g which couple an annular weight 43d to hub 430. Each yoke terminates at one end in a U- shaped fork 43h and at the other end in a guiding prong 43i and brake release stop 43k. Both forks mate engagingly with an associated prong and stop (see FIG. 6) so that in conditions of slow speed rotation (i.e., curtain lift) the gravitational forces of the two weights 43d counteract each other preventing application of the brake because of gravity. They also serve to reduce noise by preventing the weights from repeatedly falling from an apply position to a release position as the weights are alternately carried from above center to below center through rotation of hub 43a.

Brake release stop 43k of weight 43d limits the movement of the weight toward the shaft by coming against the-face of hub 43a and thus prevents interference of weights 43d with limit switch assembly 44.

FIG. 12 shows the application of anchor 23 to drum 24. The upper end of anchor 23 is formed with a hook 73. The downward end 74 of the hook is received within a drum hole 75 when nut 76 fixes the anchor to the drum after cable 3, 4 is trapped by the hook.

In the event a particular damper does not include a baffle 18, or alternately the baffle is not sufficiently strong to support housing 19, then comer bracket 35 may be applied to the upper left corner of damper l to receive finger 25 (see FIG. 13). This bracket is formed 7 with a pair of bent flanges which define an angle opening 26a to receive finger 25. 1

The detailed sequential operation of the electrical and mechanical components shown in FIGS. 6 through 13 has previously-been described with reference to the circuit diagram of FIG. 5. It should be understood, however, that the foregoing structure and operation are merely typical of a preferred embodiment, and that modifications can be made without departing from the scope of the invention.

What is claimed is:

1. in an operator for a multi-fold curtain damper having a frame or shell enveloping the damper curtain and in which the curtain is capable of opening and closing an air passage defined by the frame or shell in response to the winding and anwinding of one or more cable sections on a motor driven drum, the improvement comprising a motor having an output drive shaft with the motor including an integral brake to prevent shaft rotation when the motor is deenergized; a planetary gear selectively coupling the motor output shaft to the drum to rotate thereby the drum responsively to shaft rota tion, the planetary gear including a sun gear fixedly connected to the motor output shaft and having a common longitudinal axis of rotation therewith, a plurality of planet gears mounted on a planetary carrier and fixedly coupled to the drum to rotate thereby the drum on the foregoing longitudinal axis of rotation when the planetary carrier rotates, and an internal gear ring engaging the planet gears; an electromagnetically actuatable clutch selectively coupled to the ring gear; an electromagnet which when energized actuates the clutch to position fixedly the internal ring gear thereby rotating the planetary carrier in response to motor output shaft rotation; a limit switch including a switch actuating element coupled to the drum and responsive to a predetermined number of drum revolutions to actuate the switch to deenergize thereby the motor upon full opening of the curtain with the curtain being held in the open position by the motor brake; and switching means connected to the electromagnet to complete and energizing circuit for the electromagnet to effect thereby clutch engagement to wind a cable about the drum until the motor energizing circuit is opened by the limit switch and the switching means when opening the energizing circuit disengages the clutch to effect drum release which enables the curtain to lower thus closing the damper.

2. The combination of claim 1 comprising a second shaft rotating responsively with the drum, the limit switch being fixedly mounted adjacent the second shaft and connected in a drum driving motor actuating circuit, and the switch actuating element being coupled to the second shaft and being responsive to a predetermined number of rotations of the second shaft in the curtain raising direction to drive the switch actuating element into operational engagement with the switch to .deenergize the motor to limit the elevation of the curtain during the curtain opening operation.

3. The combination of claim 2 in which the switch actuating element includes a threaded sleeve mounted on a threaded extension portion of the second shaft, and a stop which defines the number of relative rotational turns of the sleeve which can be made on the threaded extension portion of the second shaft after which number of turns the switch actuating element rotates with the second shaft to actuate the switch.

4. The combination of claim 2 in which the switch actuating element includes a switch actuating finger projecting from the threaded extension which is driven into operational engagement with the switch to deenergize the motor to limit the elevation of the curtain during the curtain opening operation.

5. The combinationof claim 4 including a stop element fixed relative the damper, and a second finger projecting from the threaded extension into engagement with the stop element to limit the angular rotation of the actuating element when the curtain is lowered.

6. The combination of claim 1 in which the clutch includes a spring actuated pawl which is engaged to stop the rotation of the internal gear ring.

7. The combination of claim 6 in which the clutch further includes an electromagnetically actuated latch which selectively engages the pawl to prevent rotation of the internal gear ring.

t i i i l 

1. IN AN OPERATOR FOR A MULTI-FOLD CURTAIN DAMPER HAVING A FRAME OR SHELL ENVELOPING THE DAMPER CURTAIN AND IN WHICH THE CURTAIN IS CAPABLE OF OPENING AND CLOSING AN AIR PASSAGE DEFINED BY THE FRAME OR SHELL IN RESPONSE TO THE WINDING AND ANWINDING OF ONE OR MORE CABLE SECTIONS ON A MOTOR DRIVEN DRUM, THE IMPROVEMENT COMPRISING A MOTOR HAVING AN OUTPUT DRIVE SHAFT WITH THE MOTOR INCLUDING AN INTEGRAL BRAKE TO PREVENT SHAFT ROTATION WHEN THE MOTOR IS DEENERGIZED; A PLANETARY GEAR SELECTIVELY COUPLING THE MOTOR OUTPUT SHAFT TO THE DRUM TO ROTATE THEREBY THE DRUM RESPONSIVELY TO SHAFT ROTATION, THE PLANETARY GEAR INCLUDING A SUN GEAR FIXEDLY CONNECTED TO THE MOTOR OUTPUT SHAFT AND HAVING A COMMON LONGITUDINAL AXIS OF ROTATION THEREWITH, A PLURALITY OF PLANET GEARS MOUNTED ON A PLANETARY CARRIER AND FIXEDLY COUPLED TO THE DRUM TO ROTATE THEREBY THE DRUM ON THE FOREGOING LONGITUDINAL AXIS OF ROTATION WHEN THE PLANETARY CARRIER ROTATES, AND AN INTERNAL GEAR RING ENGAGING THE PLANET GEARS; AN ELECTROMAGNETICALLY ACTUATABLE CLUTCH SELECTIVELY COUPLED TO THE RING GEAR; AN ELECTROMAGNET WHICH WHEN ENERGIZED ACTUATES THE CLUTCH TO POSITION FIXEDLY THE INTERNAL RING GEAR THEREBY ROTATING THE PLANETARY CARRIER IN RESPONSE TO MOTOR OUTPUT SHAFT ROTATION; A LIMIT SWITCH INCLUDING A SWITCH ACTUATING ELEMENT COUPLED TO THE DRUM AND RESPONSIVE TO A PREDETERMINED NUMBER OF DRUM REVOLUTIONS TO ACTUATE THE SWITCH TO DEENERGIZE THEREBY THE MOTOR UPON FULL OPENING OF THE CURTAIN WITH THE CURTAIN BEING HELD IN THE OPEN POSITION BY THE MOTOR BRAKE; AND SWITCHING MEANS CONNECTED TO THE ELECTROMAGNET TO COMPLETE AND ENERGIZING CIRCUIT FOR THE ELECTROMAGNET TO EFFECT THEREBY CLUTCH ENGAGEMENT TO WIND A CABLE ABOUT THE DRUM UNTIL THE MOTOR ENERGIZING CIRCUIT IS OPENED BY THE LIMIT SWITCH AND THE SWITCHING MEANS WHEN OPENING THE ENERGIZING CIRCUIT DISENGAGES THE CLUTCH TO EFFECT DRUM RELEASE WHICH ENABLES THE CURTAIN TO LOWER THUS CLOSING THE DAMPER.
 2. The combination of claim 1 comprising a second shaft rotating responsively with the drum, the limit switch being fixedly mounted adjacent the second shaft and connected in a drum driving motor actuating circuit, and the switch actuating element being coupled to the second shaft and being responsive to a predetermined number of rotations of the second shaft in the curtain raising direction to drive the switch actuating element into operational engagement with the switch to deenergize the motor to limit the elevation of the curtain during the curtain opening operation.
 3. The combination of claim 2 in which the switch actuating element includes a threaded sleeve mounted on a threaded extension portion of the second shaft, and a stop which defines the number of relative rotational turns of the sleeve which can be made on the threaded extension portion of the second shaft after which number of turns the switch actuating element rotates with the second shaft to actuate the switch.
 4. The combination of claim 2 in which the switch actuating element includes a switch actuating finger projecting from the threaded extension which is driven into operational engagement with the switch to deenergize the motor to limit the elevation of the curtain during the curtain opening operation.
 5. The combination of claim 4 including a stop element fixed relative the damper, and a second finger projectIng from the threaded extension into engagement with the stop element to limit the angular rotation of the actuating element when the curtain is lowered.
 6. The combination of claim 1 in which the clutch includes a spring actuated pawl which is engaged to stop the rotation of the internal gear ring.
 7. The combination of claim 6 in which the clutch further includes an electromagnetically actuated latch which selectively engages the pawl to prevent rotation of the internal gear ring. 